Problem: Solve for $x$ : $2x - 9 = 9x + 8$
Solution: Subtract $2x$ from both sides: $(2x - 9) - 2x = (9x + 8) - 2x$ $-9 = 7x + 8$ Subtract $8$ from both sides: $-9 - 8 = (7x + 8) - 8$ $-17 = 7x$ Divide both sides by $7$ $\dfrac{-17}{7} = \dfrac{7x}{7}$ Simplify. $-\dfrac{17}{7} = x$